When working with various cropped images, it is a shame that the Watermark is not scaling with the cropping. It should be set to a percentage of image width, and stay so regardless of resolution in finished image. Should be different for landscape and portrait.
The export tool in combination with watermarks is partly buggy since years (it is a known and acknowledged bug). So, please modify the whole watermark feature so that it is working properly. :-)
A correct scaling of the watermark is absolutely appreciated. :-)